Pneumatically operated fuel supply system for automobiles



CARBURETO/E Oct. 27, 1936. A, A LANE "2,059,005 PNEUMATICALLY OPERAT-ED FUEL SUPPLY SYSTEM FOR AUTOMOBILES Filed May 18, 1954 I W/NDSHIELD n F 1 WIPEIE I 22 v qcuuM 27 v I y SUCTION H LINE 78 M cARBu/eE'To/z ||||n PRESSURE f FUEL LINE I l NE f INTAKE MANIFOLD v 2 7/ M F'UEL LINE EXHAUST 4 l MUFFLER MANIFOLD 7 k 4 56 EXHAUST cL n /vs/a PRESSURE 4N0 c 'oLse 8 20 FUEL LINE PRESSURE 72 h a m i .96 \SUCT/O/V FLOAT CHECK VALVE l arranged to Patented Oct. 27, 1936 UNITED STATES 2,059,005 PNEUMATICALLY OPERATED FUEL SUPPLY SYSTEM Abbott A. Lane. County, Pa., velopment Company, ration of Delaware FOR AUTOMOBILES O'Hara Township, Allegheny assignor to Gulf Research & De-

Pittsburgh, Pa., a corpo- Applicatlon May 18, 1934, Serial 110,726,381

3 Claims.

This invention relates to pneumatically operated fuel supply systems for automobiles; and it comprises, in an automobile having an engine with the usual carburetor, intake conduit and 5 open exhaust conduit, a fuel system comprising a main fuel tank, an open pressure connection between the exhaust conduit and the main tank, and an independent suction operable fuel supply device operable by engine intake suction and feed fuel from the main tank to the carburetor, whereby adequate fuel feed is maintained under all engine operating conditions; all as more fully hereinafter set forth and as claimed. In automobiles the main fuel supply tank is in general at a lower level than the carburetor, and

r it is usual to provide a suction operable device of some sort for drawing fuel from the tank and supplying it tothe carburetor. Ordinarily the suction device takes the form of a vacuum tan go a float-controlled tank apparatus mounted above the engine in suction communication with the intake manifold and adapted to draw fuel from the main tank and supply it under gravity head to the carburetor. It is, moreover, usual to employ intakemanifold suction for operating other accessories besides the fuel supply, such as windshield wipers, horns, clutches and servo brakes; said accessories being in more or less general use and usually having mechanical suction responsive means such as pistons, diaphragms or bellows.

In suction systems of this sort the intake manifold is tapped at some point between the cylinders and the throttle. The suction in this region is high when t throttle is closed or nearly closed, but drops rapidly at larger throttle openings. when the throttle is wide open, as in high speed work or under heavy pulling, there is insufficient suction for proper operation of the fuel supply device. Vacuum tanks are commonly to equipped with reserve storage capacity for maintaining a fuel supply to the carburetor during short intervals of wide open throttle operation; but sometimes this expedient is inadequate.

The most important of the suction-operated 45 systems mentioned is of course the fuel supply system. In view of the serious disadvantages inherent in the vacuum tank system described, pressure feed systems were developed. In these systems the main fuel tank is made pressure tight, 50 and air or gas under pressure is supplied to this tank from an air compressor, or direct from a cylinder of These systems require a manually operable aircompressor for establishing an initial pressure 56 before startins up,

the engine through a check valve.-

(01. its-30.5

This type of fuel feed system has several advantages, among them being constant fuel supply at all speeds, elimination of evaporation in the main tank (the tank being always closed airtight) and elimination of vapor lock in the fuel 5 line. The advantages over vacuum systems are particularly important in high speed work. Nevertheless, this type of system is obsolescent; the reason for this residing in its several serious inherent disadvantages. In case of a leak in the sys- 10 tem such as a leaky car uretor float valve, then when the car is left standing, the gasoline will continue to leak until the air pressure in the tank has dropped to the pressure outside. If the fuel tank is only'partly filled, the fuel tank may em 1 ty itself completely. In case of a collision, if the gasoline tank is punctured, or the fuel line broken, a stream of gasoline will burst forth under pressure, which may result in serious fires.

A third objection to the straight pressure feed system is the annoyance of having to establish pressure in the gasoline tank by the use of a handpump before starting the car, which operation is frequently forgotten, and the battery run down in an ineffective effort to start without pressure 25 for fuel supply. Also, the cap in the main tank must be kept perfectly tight, in order to conserve the limited amount of pressure developed by the small engine compressor or by the single engine cylinder. 30

The present invention is an improvement over such systems. I provide a fuel supply device adapted to be operable by suction, and to utilize intake manifold suction in the usual way; but I also utilize exhaust pressure. The fuel supply device is modified to adapt it for pressure as well as suction operation; and the exhaust manifold of the engine is tapped asa.source of operating pressure. As stated, intake suction decreases with increasing throttleopening. Exhaust 40 pressure, however, increases with throttle opening. Intake suction and exhaust pressure are complementary, soto speak; the differential pressure is fairly constant underall conditions. The fuel supply system functions efliciently and equal- 1y well under all conditions and speeds. The fuel supply device used is analogous to the ordinary vacuum tank but with additional valve means for preventing flooding of the vacuum tank, and certain other additional valve means in the fuel line. Appropriate cleaning and cooling means are provided for the exhaust gases.

In the accompanying drawing showing one form of a specific embodiment of my invention;

Fig. 1 is a diagram of a complete fuel supply system showing all suction and pressure connections, and

Fig. 2 shows the suction-pressure tank in detail and and the usual exhaust manmuiiler H. The fuel supply fuel tank l5 adapted The system described thus far is analogous to ordinary automobile suction systems.

According to the invention I utilize the engine exhaust as a source of pressure, tapping the exhaust manifold as at 32 by pressure conduit 33. The exhaust may be tapped either on the manigases, this being indicated diagrammatically at 34. The cleaner may comprise a simple chamber adapted to allow dust, oil, etc. to be precipitated from the exhaust gases; or the chamber may be fitted with bailles to facilitate the precipitation. In any case the cleaner and cooler are in open communication with the exhaust manifold and with the pressure conduits, no check valves or the like being used, so that pressure in the fuel system is released immediately upon stopping the engine. In my system all parts are at atmospheric pressure when the engine is not running, hence there is no chance for aggravation of leakage. For cooling the hot gases I find it advantageous to provide heat exchange between the hot gases and the engine cooling water. The cooler may be of the surface cooler type, cooling water being circulated therethrough by the engine pump. Heat exchange means between the cooling water and the exhaust gases are conventionally shown as water connections 35, 36 in the cooling water circulation system, entering the cleaner and cooler as shown. Instead of cooling by water the exhaust gases may be cooled by air if appropriate heat exchange means are provided, advantageously mounted in front of the engine radiator and adapted to receive a strong flow of cool air.

Cooling means are not essential as far as the fuel supply system is concerned, and may be omitted ii the system comprises only the fuel supply. But when other accessories such as windshield Wipers are gases through the The cleaner and cooler is adapted to supply cleaned and cooled gas under pressure through out1et31. As shown, a branch pressure line 38 runs from outlet 31 to the top of the main fuel tank.

In operation, the engine being run at any speed, suction is developed in line 2| and pressure in line 31. Suction is applied to the vacuum tank and pressure is applied to the main fuel tank. The net pressure differential is substantially constant whatever the speed and load conditions of the engine.

Fig. 2 illustrates the vacuum tank construction in detail;

and having a check valve An inner vacuum well or chamber 65 is sustop of the outer casing, as shown. is sealed off from communication with the fuel reservoir proper except through a lower outlet 66 controlled by a check valve 61 allowing flow from, but not to, the inner chamber.

Inside the vacuum chamber is a float 6B mountconnection 22, respectively. Valves yoked on a U-shaped member valve II and member 17 are pivotally attached as The mechanical operation 01 the vacuum tank is as follows: The float is shown in lower position,

arm 94 rises sufliciently to lift the coil spring above pivot 8| (dead center), whereupon the spring snaps up and the upturned end 9| of bar 9|] contacts with the end of rocking bar 18. Bar

I8 is tipped upward, closing valves 12 and 13 and opening valve ll; Upon falling of the float thev valves are snapped to the former position. The linkage and spring arrangement is for the purpose of providing quick and positive opening and closing of the valves.

The operation of the vacuum tank and the rest of thesystem is as follows: At low speeds movement of fuel is mainly or partially by intake suction. Assume valve 53 closed; this valve is only opened when it is desired to make use of the bypass system as will be described. The float is shown-in Fig. 2 as in low position, the supply of fuel in the vacuum tank being low. Poppet valve II is closed; valves 12 and I3 are opened. The engine being running, fuel is drawn from the main tank through line 20 under intake suction (acting through line 22) and into the inner well 65. Check valve 61 being closed fuel cannot flow from the outer casing into the inner well. Fuel is supplied to the engine by gravity through line l9 running to the carburetor.

The main fuel tank is under exhaust pressure, and this pressure assists in moving fuel from the main tank to the vacuum tank. At higher speeds most of the fuel movement is performed by exhaust pressure.

The valve linkage is for the purpose of closing off admission of fuel to the vacuum tank when the tank is full and allowing fuel to flow from the inner well to the outer casing. As the inner well gradually fills with fuel under the influence of intake suction and exhaust pressure, the float,

rises, and as it reaches a level near the top, springs the valve 1| open and valves 12 and I3 closed. Open valve H allows air to flow into the tank, permitting fuel to flow therefrom. Valves I2 and 13 close off the fuel line and suction line respectively. The level of fuel in the inner well being higher than in theouter casing, fuel flows from the inner well to the outer casing through check valve 61. Valve 12 is advantageously made quite small in diameter, so that it will remain closed against pressures developed in the fuel line under exhaust pressure.

The valves remain in the position just described until the level of fuel in the vacuum tank drops below a certain point, whereupon the float serves to snap the valves back to the position shown in Fig. 2. The cycle of operation is repeated. Fuel is again drawn into the vacuum tank.

At high speeds, intake suction is low and exhaust pressure is high, exhaust pressure serving to do most of the operation of the fuel supply system. In Fig. 2 I have shown a bypass system which makes it possible to use exhaust pressure directly for forcing fuel from the main tank to the carburetor, bypassing the vacuum tank, when the engine running conditions are such that exhaust pressure is high. This system comprises check valve 56 in conduit I9, bypass conduit 5| and check valve 52. An ordinary gate valve 53 allows the bypass arrangement to be thrown in and out of action as desired. In operation using the bypass, at low engine speeds fuel is moved principally by intake suction and assisted by exhaust pressure in the manner desscribed. Check valve 52 will be closed, as shown, as long as the pressure on one side of it due to the head in the vacuum tank is greater than the pressure on the other side due to exhaust pressure on fuel in lines 20 and 5|. when the engine is running under open throttle, however, a time comes when the exhaust pressure in the main fuel tank and conduits 20 and 5| exceeds the gravity head of the vacuum tank, whereupon check valve 52 is opened, taking the position shown in dotted lines in Fig. 2. Fuel then flows direct from the main fuel tank through conduits 20, 51 and I9, to the carburetor. Check valve 56 prevents fuel from being forced reversely into the vacuum tank through conduit l9. When exhaust pressure drops below the value equal to the hydrostatic head of the vacuum tank, check valve 52 closes and the vacuum tank comes into operation again. Valve 53 allows the bypass to be thrown in or out of operation. The bypass system is not essential, and may be omitted, check valves 52 and 56 and conduit 5| being omitted.

It is seen that in this system I have provided a new and useful improvement in automobile fuel supply systems, which makes possibleuniform and constant operation thereof under all conditions, while adding little to the complication of the apparatus and without taking any power from the engine. The system has all the advantages of both vacuum systems and ordinary pressure systems, with the additional advantage over ordinary pressure systems that in the new system pressure automatically drops to zero when the engine is not running. The exhaust conduit being in open communication with the atmosphere, pressure can only exist in the exhaust conduit when the engine is running.

If desired, pneumatic windshield wipers 0 other pneumatically operable devices may be readily connected into the pressure and suction conduits; the accessories in this case being modifled for actuation both by suction and pressure.

Thus, a windshield wiper 24, arranged for suction and pressure operation, may be used with the system; the wiper being connected into suction line 2| as at 3| by a suction pipe 30, and into communication with exhaust gas outlet 31 through a.

pressure pipe 39. Other pneumatic devices of this type can be readily connected into the system. Capped couplings l0 ,and 4| are shown provided in pipes 2| and 39, for this purpose.

What I claim is:

1. In an automobile having an engine with the usual carbureter, an intake conduit and an exhaust conduit in open communication from the I engine exhaust valves to the atmosphere, improved fuel supply means comprising a capped main fuel tank and an open pressure connection between the exhaust conduit and the main fuel tank so arranged that when and only when the engine is running, positive pressure direct from the exhaust conduit is put on the fuel in the main tank, and a vacuum tank arranged to draw fuel from the main tank by intake .suction and to deliver fuel to the carbureter by gravity, said vacuum tank comprising a reservoir chamber, a float chamber arranged in one-way communication with the reservoir chamber, a fuel line leading from the main tank to the float chamber, a suction line from the float chamber to the intake conduit, a float in the float chamber, a vent for the float chamber, valves for covering and un-,- covering the vent, the fuel line inlet, and the suction line inlet, and linkage means operable by the float and so constructed and arranged as to close the valves for the suction line and the fuel line supply is maintained to the the main fuel tank to put. the fuel tank under positive pressure when theengine is running, a

7 vacuum tank adapted to draw fuel from the main tank by intake suction andto deliver fuel to the carburetor by gravity, the vacuum tank having valve means adapted to cut off flow from the main fuel tank when the vacuum tank is full, a

conduit leading direct from-themain fuel tank to the carburetor, and check valve means in said conduit arranged to permit flow of fuel direct aosaooc:

from the main fuel tank-to the carburetor under exhaust pressure when exhaust pressureis high.

, 3. In an automobile having an engine with the usual carburetor and intake conduit and an exhaust conduit in open communication from the engine exhaust valves to the atmosphere, a capped main fuel tank and an open pressure connection between the exhaust conduit and the main fuel tank so arranged that when and only when the engine is running positive pressure direct from the exhaust. conduit is put on the fuel in the main tank, anda suction operable fuel supply device independent of said pressure connection and in operative fluid connection with the enginet intake and arranged to feed fuel to the carburetor and to draw fuel from the main tank when intake suction is high so that adequate fuel "feed is maintained under all engine operating conditions. ABBO'I'I A. LANE.. 

